Nucleosynthesis during the Early History of the Solar System

Abundances in terrestrial and meteoritic matter indicate that the synthesis of D^2, Li^6, Li^7, Be^9, B^(10) and B^(11) and possibly C^(13) and N^(15) occurred during an intermediate stage in the early history of the solar system. In this intermediate stage, the planetary material had become largely separated, but not completely, from the hydrogen which was the main constituent of primitive solar material. Appropriate physical conditions were satisfied by solid planetesimals of dimensions from 1 to 50 metres consisting of silicates and oxides of the metals embedded in an icy matrix. The synthesis occurred through spallation and neutron reactions simultaneously induced in the outer layers of the planetesimals by the bombardment of high energy charged particles, mostly protons, accelerated in magnetic flares at the surface of the condensing Sun. The total particle energy was approximately 10^(45) ergs while the average energy was close to 500 MeV per nucleon. Recent studies of the abundance of lithium in young T Tauri stars serve as the primary astronomical evidence for this point of view. The observed abundances of lithium and beryllium in the surface of the Sun are discussed in terms of the astronomical and nuclear considerations brought forward. The isotope ratios D^2/H^1 = 1.5 × 10^(−4), Li^6/L^i7 = 0.08, and B^(10)/B^(11) = 0.23 are the basic data leading to the requirement that 10 per cent of terrestrial-meteoritic material was irradiated with a thermal neutron flux of 10^7 n/cm^2 s for an interval of 10^7 years. The importance of the (n, α) reactions on Li^6 and B^(10) is indicated by the relatively low abundances of these two nuclei. It is shown that the neutron flux was sufficient to produce the radioactive Pd^(107) and I^(129) necessary to account for the radiogenic Ag^(107) and Xe^(129) anomalies recently observed in meteorites. The short time interval, ∼ 6 × 10^7 years, required for the radioactive decays to be effective applies to the interval between the end of nucleosynthesis in the solar system and the termination of fractionation processes in the parent bodies of the meteorites. It is not necessary to postulate a short time interval between the last event of galactic nucleosynthesis and the formation of large, solid bodies in the solar nebula

Multiple Current States of Two Phase-Coupled Superconducting Rings

The states of two phase-coupled superconducting rings have been investigated. Multiple current states have been revealed in the dependence of the critical current on the magnetic field. The performed calculations of the critical currents and energy states in a magnetic field have made it possible to interpret the experiment as the measurement of energy states into which the system comes with different probabilities because of the equilibrium and non-equilibrium noises upon the transition from the resistive state to the superconducting state during the measurement of the critical currentComment: 5 pages, 5 figure

Understanding light quanta: First quantization of the free electromagnetic field

The quantization of the electromagnetic field in vacuum is presented without reference to lagrangean quantum field theory. The equal time commutators of the fields are calculated from basic principles. A physical discussion of the commutators suggest that the electromagnetic fields are macroscopic emergent properties of more fundamental physical system: the photons

EPR before EPR: a 1930 Einstein-Bohr thought experiment revisited

In 1930 Einstein argued against consistency of the time-energy uncertainty relation by discussing a thought experiment involving a measurement of mass of the box which emitted a photon. Bohr seemingly triumphed over Einstein by arguing that the Einstein's own general theory of relativity saves the consistency of quantum mechanics. We revisit this thought experiment from a modern point of view at a level suitable for undergraduate readership and find that neither Einstein nor Bohr was right. Instead, this thought experiment should be thought of as an early example of a system demonstrating nonlocal "EPR" quantum correlations, five years before the famous Einstein-Podolsky-Rosen paper.Comment: 11 pages, revised, accepted for publication in Eur. J. Phy

ОПРЕДЕЛЕНИЕ ОРГАНИЧЕСКИХ КИСЛОТ, УГЛЕВОДОВ И ПОДСЛАСТИТЕЛЕЙ В ПИЩЕВЫХ ПРОДУКТАХ И БИОЛОГИЧЕСКИ АКТИВНЫХ ДОБАВКАХ МЕТОДОМ ВЫСОКОЭФФЕКТИВНОЙ ЖИДКОСТНОЙ ХРОМАТОГРАФИИ

The content of organic acids and carbohydrates in samples of wine, juice, dairy products, dietary supplements was revealed by reverse-phase high performance liquid chromatography (HPLC). Organic acids (oxalic acid, tartaric acid, formic acid, malic acid, lactic acid, acetic acid, citric acid, succinic acid, fumaric acid, propionic acid) was determined by using spectrophotometric detection, carbohydrates (glucose, lactose, maltose, mannose, sucrose, fructose) and sweeteners (xylitol, sorbitol) - with refractometric detection. The limits of detection of organic acids in liquid samples were 0.05-2.8 mg / l, in solid 0.7-3.1%. The detection limits for carbohydrates and sweeteners in liquid samples were 0.1-0.6 g/ l, in solid samples of 0.1-0.6 %. Samples or their solutions were purified from interfering organic impurities on solid phase extraction cartridges (SPE) C18, then were analyzed by HPLC.Key words: RP HPLC, spectrophotometric detection, refractometric detection, organic acids, carbohydrates and sweeteners, food, solid-phase extraction(Russian)DOI: http://dx.doi.org/10.15826/analitika.2013.17.2.011A.M. Zaharova*, L.A. Kartsova**, I.L. Greenstein**Company "Analyte", St. Petersburg, Russian Federation**St. Petersburg State University, St. Petersburg, Russian FederationМетодом обращенно-фазовой высокоэффективной жидкостной хроматографии (ОФ ВЭЖХ) выявлено содержание органических кислот и углеводов в пробах  вина, сока, молочных продуктов, биологически активных добавках. Органические кислоты (щавелевая, винная, муравьиная, яблочная, молочная, уксусная, лимонная, янтарная, фумаровая, пропионовая) определяли с использованием спектрофотометрического детектирования; углеводы (глюкоза, лактоза, мальтоза, манноза, сахароза, фруктоза) и подсластители (ксилитол, сорбитол) - с рефрактометрическим детектированием. Пределы обнаружения органических кислот в жидких пробах составили 0.05-2.8 мг/л; в твёрдых - 4.10-5-2.10-3 % мас. Пределы обнаружения углеводов и подсластителей в жидких пробах - 0.1-0.6 г/л, в твердых - 0.1-0.6 % мас. Анализируемые пробы или их растворы  очищали от мешающих органических примесей на картриджах  для твердофазной экстракции (ТФЭ).Ключевые слова:ОФ ВЭЖХ, спектрофотометрическое детектирование, рефрактометрическое детектирование, органические кислоты, углеводы и подсластители, пищевые продукты, твердофазная экстракция.DOI: http://dx.doi.org/10.15826/analitika.2013.17.2.01

An analysis of spectra in the Red Rectangle nebula

This paper presents an analysis of a series of spectra in the Red Rectangle nebula. Only the reddest part of the spectra can safely be attributed to light from the nebula, and indicates Rayleigh scattering by the gas, in conformity with the large angles of scattering involved and the proximity of the star. In the blue, light from HD44179, refracted or scattered in the atmosphere, dominates the spectra. This paper questions the reliability of ground-based observations of extended objects in the blue.Comment: 25 figure

Reflecting optics in the diverticular eye of a deep-sea barreleye fish (Rhynchohyalus natalensis)

We describe the bi-directed eyes of a mesopelagic teleost fish, Rhynchohyalus natalensis, that possesses an extensive lateral diverticulum to each tubular eye. Each diverticulum contains a mirror that focuses light from the ventro-lateral visual field. This species can thereby visualize both downwelling sunlight and bioluminescence over a wide field of view. Modelling shows that the mirror is very likely to be capable of producing a bright, well focused image. After Dolichopteryx longipes, this is only the second description of an eye in a vertebrate having both reflective and refractive optics. Although superficially similar, the optics of the diverticular eyes of these two species of fish differ in some important respects. Firstly, the reflective crystals in the D. longipes mirror are derived from a tapetum within the retinal pigment epithelium, whereas in R. natalensis they develop from the choroidal argentea. Secondly, in D. longipes the angle of the reflective crystals varies depending on their position within the mirror, forming a Fresnel-type reflector, but in R. natalensis the crystals are orientated almost parallel to the mirror's surface and image formation is dependent on the gross morphology of the diverticular mirror. Two remarkably different developmental solutions have thus evolved in these two closely related species of opisthoproctid teleosts to extend the restricted visual field of a tubular eye and provide a well-focused image with reflective optics

Relativistic theory of inverse beta-decay of polarized neutron in strong magnetic field

The relativistic theory of the inverse beta-decay of polarized neutron, $\nu _{e} + n \to p + e ^{-}$, in strong magnetic field is developed. For the proton wave function we use the exact solution of the Dirac equation in the magnetic filed that enables us to account exactly for effects of the proton momentum quantization in the magnetic field and also for the proton recoil motion. The effect of nucleons anomalous magnetic moments in strong magnetic fields is also discussed. We examine the cross section for different energies and directions of propagation of the initial neutrino accounting for neutrons polarization. It is shown that in the super-strong magnetic field the totally polarized neutron matter is transparent for neutrinos propagating antiparallel to the direction of polarization. The developed relativistic approach can be used for calculations of cross sections of the other URCA processes in strong magnetic fields.Comment: 41 pages in LaTex including 11 figures in PostScript, discussion on nucleons AMM interaction with magnetic field is adde

Intravitreal bevacizumab injections for diabetic macular edema - predictors of response: a retrospective study

BACKGROUND: Outcomes of intravitreal antivascular endothelial growth factor injections are variable among patients with diabetic macular edema (DME). The aim of this study was to determine the ocular and systemic predictors of DME response to intravitreal bevacizumab (IVB). METHODS: Retrospective review over 2 years of 78 eyes from 54 patients. An anatomical response to IVB was defined as a 20% reduction in central macula thickness after the first course (three injections) of IVB. RESULTS: Twenty-eight percent of patients had an anatomical response after the first course of IVB. Systemic hypertension (odds ratio, 95% confidence interval: 12.1, 0.7-21) was a statistically significant predictor (P=0.025) of a good response to IVB, whereas previous macular laser was a statistically significant (P=0.0005) predictor of a poor response (0.07, 0.01-0.32). Sixty-eight percent of eyes underwent subsequent treatment for DME after the first course of IVB. The visual acuity gain at 24 months in hypertensive (0.7±3.6 letters) and nonhypertensive (5.2±3.7 letters) patients was not significantly different (P=0.41). CONCLUSION: Hypertension and previous macular laser were positive and negative predictors of response to IVB, respectively. However, long-term visual acuity changes were not significantly different between eyes with and without systemic hypertension